How much do the routes go for? I can't imagine this would be the best way to invest your money. You get yourself an apartment building and you have money coming in from rent and you have something tangible that will increase in value over time. You wouldn't be at the whim of FedEx or any other corporation. If you can get tenants whose housing costs are subsidized by the state you wouldn't even have to worry about people not paying their rent either. Just keep up on maintenance and make sure everyone behaves and gets along and you're all set. No trucks, no employees, no packages, just a building and the people that live there.
I have invested in real estate and will again but never apartments. The ROI is extremely low and the hassles and stresses of multiple renters and problems of a structure old enough to pay $500,000 would be ridiculous. After paying taxes, maintenance, carryover with evictions not be rented most of the time makes real estate a long term investment where you are banking on 2-10% annual growth. I am not saying you can't make money or fix/flip for fast money but the monthly ROI of a slum lord is very low in most circumstances.
Buy some routes and they grow 10%+ a year, just as many irritations with FedEx, fairly secure and possible to make $100,000+ a year while your routes grow. As you grow you can sell off some here and there getting all your investment back and still have multiple routes making owner $100k being fully paid back.
There are a lot of places to invest and a lot of us have but honestly it is not a bad investment in the least and has the potential to be extremely lucrative.